Self-assembly structures used for fabricating patterned magnetic media

ABSTRACT

Methods of defining servo patterns and data patterns for forming patterned magnetic media are described. For one method, a lithographic process is performed to define a servo pattern in servo regions on a substrate. The lithographic process also defines a first data pattern in data regions of the substrate. The first data pattern is then transferred to (i.e., etched into) the data regions. Self-assembly structures are then formed on the data pattern in the data regions to define a second data pattern. The servo pattern is then transferred to the servo regions and the second data pattern is transferred to the data regions. Thus, the servo pattern is defined through lithographic processes while the data pattern is defined by a combination of lithographic processes and self-assembly.

RELATED APPLICATIONS

This non-provisional patent application is a continuation of U.S. patentapplication Ser. No. 11/964,680 filed on Dec. 26, 2007, which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is related to the field of magnetic disk drive systemsand, in particular, to fabricating patterned magnetic media. Moreparticularly, a lithographic process is used to form a servo pattern anda data pattern for a patterned magnetic media. Self-assembly structuresare then built on the data pattern to further refine this pattern, butare not built on the servo pattern.

2. Statement of the Problem

Many computer systems use magnetic disk drives for mass storage ofinformation. Magnetic disk drives typically include one or more magneticrecording heads (sometimes referred to as sliders) that include readelements and write elements. A suspension arm holds the recording headabove a magnetic disk. When the magnetic disk rotates, an air flowgenerated by the rotation of the magnetic disk causes an air bearingsurface (ABS) side of the recording head to ride a particular heightabove the magnetic disk. The height depends on the shape of the ABS,disk spinning speed, pressure, and other variables. As the recordinghead rides on the air bearing, an actuator moves an actuator/suspensionarm to position the read element and the write element over selectedtracks of the magnetic disk.

On a conventional disk, the magnetic surface of the disk is continious.Binary information is recorded on the disk by polarizing a unit (calleda bit) of the disk to be one polarity (1) or the opposite polarity (0).The smaller the bit, the more information can be stored in a given area.Present magnetic recording may achieve a unit as small as 18×80nanometers. Each bit includes multiple magnetic grains, and the typicalgrain size is about 6 nanometers. Therefore, in a bit of size 18×80nanometers, there are about 40 grains.

To increase the areal density of the magnetic disk, the bit size isreduced. If the grain sizes are kept the same for smaller bit sizes,then there would be a smaller number of grains in a bit resulting insmaller signal-to-noise ratio (SNR). If the grain sizes are reducedproportionally to keep the number of grains in a bit constant forsmaller bit sizes, then the SNR would be the same. However, thesuper-paramagnetic effect may cause problems when grain sizes arereduced. The super-paramagnetic effect occurs when the magnetic grainson the disk become so tiny that ambient temperature can reverse theirmagnetic orientations. The result is that the bit is erased and the datais lost.

One solution to the problems posed by the super-paramagnetic effect isto pattern the magnetic disk. A patterned disk is created as an orderedarray of highly uniform islands, with each island capable of storing anindividual bit. Within each island, the magnetic materials are stronglycoupled so that an island behaves as a single domain, in contrast tomultiple domains in the continuous media. Because an individual magneticdomain is as large as an island, the patterned disk is thermally stableand higher densities may be achieved.

When data recording is performed on a magnetic disk, the read head andwrite head are positioned over the tracks based on a Positioning ErrorSignal (PES) that is read from servo regions on the disk. The servoregions include patterns that are used to guide the read and writeelements to the proper position on the disk. The regions where theactual data is stored are referred to herein as the data regions.

There are problems encountered when fabricating patterned media. In dataregions, the islands of the patterned media should be uniformly spacedwith very tight distribution. The precise locations and sizes of theislands are important to the SNR and the Bit Error Rate (BER) of thedata recording process. Also, to increase the areal density of the disk,the spacing and size of the islands have to be small which ischallenging for the fabrication process as the requirements may bebeyond the limits of the lithographic capabilities.

By contrast, the islands in the servo regions are typically larger insize than the data regions. Larger islands in a sync field of the servoregion advantageously lead to larger magnetic amplitudes when read by aread element which can provide a more accurate determination ofamplitude and timing in the positioning signal.

Another difference between the data regions and the servo regions isthat the islands of the data region need to be uniformly spaced, whereasthe islands in the servo regions are staggered with empty space inbetween. The arrangement of the servo region is as such to provide asensitive PES. Servo regions may have complex patterns, may have openareas, and may tolerate the size and shape fluctuations of individualislands. The data regions on the other hand have a single regularpattern, and require highly uniform island arrangement in both theposition and sizes.

One promising approach to improve the tolerance of the island locationsand sizes is to grow self-assembly structures on top of thelithographically-defined template. Then the location and size tolerancewill be improved to the level limited by the molecular mono-dispersityof the self-assembly molecules. Self-assembly structures are most stableon regular lattices, such as hexagonal close packed (HCP). A regularlattice is good for the data regions. However, in servo regions, thecomplex servo patterns do not necessarily conform easily to HCP or othersimple lattices.

Patterned media is typically fabricated using nanoimprint lithography(NIL). Nanoimprint lithography is a high-throughput method forimprinting nanometer-scale patterns on a substrate. To imprint thenanometer-scale patterns on a substrate, a master template is firstfabricated. The master template is not typically used for imprinting anactual substrate as it can be quickly worn out when a large number ofimprints are needed. The master template is expensive and time consumingto fabricate, so the master template is rather used to fabricate aplurality of stamper tools. The stamper tools are then used forimprinting the substrates to fabricate the patterned media.

To fabricate a stamper tool, the master template is pressed into a layerof polymer stamper resist material to imprint the inverse pattern of themaster template in the stamper resist material. Heat or ultraviolet (UV)irradiation may then be applied to the stamper resist material to hardenthe stamper resist material in the inverse pattern of the mastertemplate. The master template is then removed from the stamper resistmaterial leaving a stamper tool having a desired pattern. The stampertool may then be used to imprint a plurality of substrates that willform patterned media.

To imprint a substrate, the stamper tool is pressed against a thin layerof replica resist material deposited on the substrate to imprint theinverse pattern of the stamper tool in the replica resist material. Thestamper tool is then removed from the replica resist material leaving asubstrate with a desired resist pattern covering the substrate. Anetching process, such as Reactive Ion Etching (RIE), may then beperformed to pattern the substrate according to the resist pattern. Asimilar process is performed to pattern many substrates using thestamper tool.

The master template is thus fabricated to have a desired servo patternand a desired data pattern so that these patterns may be transferred toa substrate to form a patterned magnetic media. It remains a problem todefine the servo pattern and the data pattern on the master template, asthese patterns do not conform to the same island size, shape, anddistribution.

SUMMARY OF THE SOLUTION

Embodiments of the invention solve the above and other related problemsby using a lithographic process to define a servo pattern in the servoregions, and to define a data pattern in the data regions. The servoregions are then covered, and the data pattern is transferred to thedata regions. Self-assembly structures are then built on the datapattern in the data regions to define a self-assembly pattern in thedata regions. The self-assembly pattern is more uniform and precise thanthe data pattern formed through lithographic processes. Thus, bybuilding self-assembly structures in the data regions, the islands ofthe data regions may be patterned in a uniform manner with preciselocations and sizes. By using a lithographic process in the servoregions, the islands of the servo regions may be patterned to be largerin size and staggered in the desired fashion. Also, the servo patternand the data pattern are defined in the same lithographic process, sothere is a precise registration between the servo regions and the dataregions.

One embodiment of the invention comprises a method of defining servopatterns and data patterns for a patterned magnetic media. To start, alithographic process is performed to define a servo pattern in servoregions on a substrate. The lithographic process also defines a firstdata pattern in data regions of the substrate. The first data pattern isthen transferred to (i.e., etched into) a shallow surface layer of thedata regions. When the first data pattern is transferred to the dataregions, a protective layer may be formed over the servo regions so thatthe servo pattern is not transferred at this time. Self-assemblystructures are then formed on the first data pattern in the data regionsto define a second data pattern. The top surface of the data regions haschemical or topographic contrast with the self-assembly structures, sothe self-assembly structures assemble themselves in a uniform manner onthe first data pattern and thus “fix” non-uniformities in the first datapattern. The servo pattern is then transferred to the servo regions andthe second data pattern is transferred to the data regions. Thus, theservo pattern is defined through lithographic processes while the datapattern is defined by a combination of lithographic processes andself-assembly. The data pattern may be formed in the desired uniformfashion (i.e., HCP ordering) with self-assembly while the servo patternmay be formed in a more non-uniform fashion with lithography.

The invention may include other exemplary embodiments described below.

DESCRIPTION OF THE DRAWINGS The same reference number represents thesame element or same type of element on all drawings.

FIG. 1 illustrates a magnetic disk drive system.

FIG. 2 is a top view of a magnetic recording disk.

FIG. 3 illustrates exemplary patterns in servo regions and data regionsof a magnetic recording disk.

FIG. 4 is a flow chart illustrating a method of defining servo patternsand data patterns for a patterned magnetic media in an exemplaryembodiment of the invention.

FIGS. 5-9 are cross-sectional views of a master template beingfabricated according to the method of FIG. 4 in an exemplary embodimentof the invention.

FIG. 10 is a flow chart illustrating a more detailed method of definingservo patterns and data patterns for a patterned magnetic media in anexemplary embodiment of the invention.

FIGS. 11-21 are cross-sectional views of a master template beingfabricated according to the method of FIG. 10 in an exemplary embodimentof the invention.

FIG. 22 is a flow chart illustrating another method of defining servopatterns and data patterns for a patterned magnetic media in anexemplary embodiment of the invention.

FIGS. 23-28 are cross-sectional views of a master template beingfabricated according to the method of FIG. 22 in an exemplary embodimentof the invention.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1-28 and the following description depict specific exemplaryembodiments of the invention to teach those skilled in the art how tomake and use the invention. For the purpose of teaching inventiveprinciples, some conventional aspects of the invention have beensimplified or omitted. Those skilled in the art will appreciatevariations from these embodiments that fall within the scope of theinvention. Those skilled in the art will appreciate that the featuresdescribed below can be combined in various ways to form multiplevariations of the invention. As a result, the invention is not limitedto the specific embodiments described below, but only by the claims andtheir equivalents.

FIG. 1 illustrates a magnetic disk drive system 100. Magnetic disk drivesystem 100 includes a spindle 102, a magnetic recording disk 104, amotor controller 106, an actuator 108, an actuator/suspension arm 112,and a recording head 114. Spindle 102 supports and rotates magneticrecording disk 104 in the direction indicated by the arrow. A spindlemotor (not shown) rotates spindle 102 according to control signals frommotor controller 106. Recording head 114 is supported byactuator/suspension arm 112. Actuator/suspension arm 112 is connected toactuator 108 that is configured to rotate in order to position recordinghead 114 over a desired track of magnetic recording disk 104. Magneticdisk drive system 100 may include other devices, components, or systemsnot shown in FIG. 1. For instance, a plurality of magnetic disks,actuators, actuator/suspension arms, and recording heads may be used.

When magnetic recording disk 104 rotates, an air flow generated by therotation of magnetic disk 104 causes an air bearing surface (ABS) ofrecording head 114 to ride on a cushion of air at a particular heightabove magnetic disk 104. The height depends on the shape of the ABS. Asrecording head 114 rides on the cushion of air, actuator 108 movesactuator/suspension arm 112 to position a read element (not shown) and awrite element (not shown) in recording head 114 over selected tracks ofmagnetic recording disk 104.

FIG. 2 is a top view of magnetic recording disk 104. Magnetic recordingdisk 104 may be fabricated for perpendicular recording or longitudinalrecording. Magnetic recording disk 104 has a plurality of servo regions202 and a plurality of data regions 204. Data regions 204 are patternedin a desired manner to define a plurality of concentric tracks. Servoregions 202 are patterned in a desired manner in order to providepositional signals to precisely position a recording head over thetracks in data regions 204.

FIG. 3 illustrates exemplary patterns of servo regions 202 and dataregions 204. Servo regions 202 may each include a sync field andplurality of burst fields (A-D). The horizontal dotted lines in FIG. 3illustrate data tracks of magnetic recording disk 104. The islands inthe sync field and the burst fields may be larger in size and have anon-uniform shape. Conversely, the islands in data regions 204 shouldhave a uniform size, a uniform shape, and should be precisely definedalong a track. The islands in data regions 204 are in an arrayresembling an HCP structure. There may be other servo patterns whichhave complex structures which are also not suitable for self-assemblystructures.

As previously stated, it is a problem to pattern a magnetic media, suchas magnetic recording disk 104, so that the islands in data regions 204have a uniform pattern while servo regions 202 have non-uniformpatterns. FIG. 4 describes a method of defining servo patterns and datapatterns for a patterned magnetic media, which effectively allows forthe different patterns of data regions 204 and servo regions 202.

FIG. 4 is a flow chart illustrating a method 400 of defining servopatterns and data patterns for a patterned magnetic media in anexemplary embodiment of the invention. Method 400 is illustrated asfabricating a master template. FIGS. 5-8 are cross-sectional views of amaster template 500 being fabricated according to method 400. Mastertemplate 500 may be used to imprint a substrate to fabricate a patternedmagnetic media, or may be used to form one or more stamper tools thatimprint the substrate to fabricate the patterned magnetic media. Method400 may also be used to pattern a substrate of a patterned magneticmedia directly, which is independent from fabricating a master template.

Step 402 comprises performing a lithographic process to define a servopattern in servo regions 504 on a substrate 502 (see FIG. 5). Thelithographic process in step 402 also defines a first data pattern indata regions 506 of substrate 502. FIG. 5 is a cross-sectional view ofmaster template 500 with the servo pattern and the first data patterndefined according to step 402. The portion of substrate 502 that isshown in FIG. 5 illustrates a servo region 504 and a data region 506,although a subsequently formed master template 500 will include multipleservo regions 504 and data regions 506. Those skilled in the art willappreciate that the lithographic process in step 402 is used to patterna photoresist that is deposited on substrate 502. Substrate 502 may havea surface or top coating (not shown) of a seed layer to alter surfacechemistry of substrate 502, such as to attract self-assembly materials.

The first data pattern defined in the lithographic process is notprecise enough to uniformly pattern data regions 506. Thus, the firstdata pattern is the pattern upon which self-assembly structures will bebuilt in following steps. However, the lithographic process is preciseenough to pattern servo regions 504 in a desired manner, and thusself-assembly structures are not used in servo regions 504.

Step 404 of method 400 comprises transferring the first data pattern toa shallow surface layer of data regions 506. FIG. 6 is a cross-sectionalview of master template 500 with the first data pattern transferred indata regions 506 according to step 404. Transferring the first datapattern may comprise etching the first data pattern into a top surfaceof substrate 502 in data regions 506 so that self-assembly structuresmay be formed on the first data pattern. When step 404 is performed, aprotective layer (not shown) may be formed over servo regions 504 sothat the servo pattern is not transferred at this time, which isillustrated in subsequent embodiments.

Step 406 comprises forming self-assembly structures 702, such as fromdi-block polymers, on the first data pattern in data regions 506 (seeFIG. 7). FIG. 7 is a cross-sectional view of master template 500 withself-assembly structures 702 formed on the first data pattern accordingto step 406. The top surface of substrate 502 has chemical ortopographic contrast with self-assembly structures 702. Due to theirinherent properties, self-assembly structures 702 uniformly build uponthe first data pattern and thus “fix” non-uniformities in the first datapattern by assembling themselves in a uniform manner. The precise anduniform pattern formed by self-assembly structures 702 defines a seconddata pattern (also referred to as a self-assembly pattern) in dataregions 506. Those skilled in the art may use different methods offorming self-assembly structures 702. Also, those skilled in the artwill appreciate that the first data pattern and the second data patternmay be different. There may not necessarily be one-to-one correlation offeatures in the first data pattern and the second data pattern. Thefirst data pattern is used as a guide for forming the self-assemblystructures 702 that are used to define the second data pattern.

Step 408 comprises transferring the servo pattern to the servo regions504 and transferring the second data pattern to the data regions 506.FIG. 8 is a cross-sectional view of master template 500 with the servopattern transferred and the second data pattern transferred according tostep 408. In transferring the servo pattern, an etching process may beperformed to etch around the photoresist defined in the initiallithographic process. The etching process etches the servo pattern intosubstrate 502 in servo regions 504. In transferring the second datapattern, the same or another etching process may be performed to etcharound the self-assembly structures 702 (see FIG. 7). The etchingprocess etches the second data pattern into substrate 502 in dataregions 506. Any desired etching or removal process may be employed instep 408. The photoresists and self-assembly structures may then beremoved leaving the master template 500 having the desired pattern inservo regions 504 and data regions 506. FIG. 9 is a cross-sectional viewof master template 500 with the desired patterns.

In step 408, the servo pattern and the second data pattern may betransferred in the same or similar etching process. However, it may bedesirable to transfer the servo pattern and the second data patternseparately. For instance, different etch rates may be used, differentetch depths may be used, etc. To transfer the patterns separately, theservo regions may be covered with a protective layer while the seconddata pattern is transferred to the data regions 506. The servo regionsmay then be uncovered, and the data regions may be covered with aprotective layer while the servo pattern is transferred to the servoregions 504.

Method 400 and variations thereof advantageously provide an effectiveway of defining different patterns in servo regions 504 and data regions506. Also, the servo pattern and the first data pattern are defined inthe same lithographic process, so there is a precise registrationbetween the servo regions 504 and the data regions 506.

FIG. 10 is a flow chart illustrating a more detailed method 1000 ofdefining servo patterns and data patterns for a patterned magnetic mediain an exemplary embodiment of the invention. Method 1000 is illustratedas fabricating a master template. FIG. 10 illustrates just oneembodiment, and variations of method 1000 may be used to fabricatemaster templates as described herein. FIGS. 11-21 are cross-sectionalviews of a master template 1100 being fabricated according to method1000.

FIG. 11 is a cross-sectional view of master template 1100 duringfabrication that includes a substrate 1102. The portion of substrate1102 that is shown illustrates a servo region 1104 and a data region1106 although a subsequently formed master template will includemultiple servo regions 1104 and data regions 1106.

Step 1002 of method 1000 comprises forming or depositing a base layer1202 on substrate 1102 (see FIG. 12). FIG. 12 is a cross-sectional viewof master template 1100 with base layer 1202 formed according to step1002. Base layer 1202 is formed from a material that attractsself-assembly materials, such as polymers or monomers. Step 1004comprises forming or depositing a photoresist 1302 on base layer 1202(see FIG. 13). FIG. 13 is a cross-sectional view of master template 1100with resist 1302 formed according to step 1004. Step 1006 comprisesperforming a lithographic process, such as electron beam lithography, todefine a servo pattern in resist 1302 in servo regions 1104 (see FIG.14). The lithographic process in step 1006 also defines a first datapattern in resist 1302 in data regions 1106. FIG. 14 is across-sectional view of master template 1100 with resist 1302 patternedaccording to step 1006. The first data pattern defined in thelithographic process is not precise enough to uniformly pattern dataregions 1106. Thus, the first data pattern is the pattern upon whichself-assembly structures will be built in following steps. However, thelithographic process is precise enough to pattern servo regions 1104 ina desired manner, and thus self-assembly structures are not used inservo regions 1104.

Step 1008 comprises forming a protective layer 1502 on resist 1302 inservo regions 1104 (see FIG. 15). FIG. 15 is a cross-sectional view ofmaster template 1100 with protective layer 1502 formed according to step1008. Protective layer 1502 comprises any type of protective materialthat covers and protects servo regions 1104, such as a diamond-likecarbon (DLC) material. Step 1010 comprises performing an etching processto etch the first data pattern in base layer 1202 in data regions 1106.For example, an etching process, such as Reactive Ion Etching (RIE), maybe performed to etch the portions of base layer 1202 exposed by resist1302. FIG. 16 is a cross-sectional view of master template 1100 afterthe etching process according to step 1010. The etching processtransfers the first data pattern 1602 to base layer 1202. Step 1012comprises removing resist 1302 in data regions 1106 (see FIG. 17). FIG.17 is a cross-sectional view of master template 1100 with resist 1302removed in data regions 1106 according to step 1012. After resist 1302is removed, the first data pattern 1602 remains in data regions 1106.

Step 1014 comprises forming self-assembly structures 1802, such as fromdi-block polymers, on the first data pattern 1602 in data regions 1106(see FIG. 18). FIG. 18 is a cross-sectional view of master template 1100with self-assembly structures 1802 formed according to step 1014. Thoseskilled in the art may use different methods of forming self-assemblystructures 1802. Due to their inherent properties, self-assemblystructures 1802 uniformly build upon the first data pattern 1602 that isetched in data regions 1106. Self-assembly structures 1802 thus “fix”non-uniformities in the first data pattern 1602 by assembling themselvesin a uniform manner. The precise and uniform pattern formed byself-assembly structures 1802 defines a second data pattern in dataregions 1106. Again, those skilled in the art will appreciate that thefirst data pattern and the second data pattern may be different, as thefirst data pattern is used as a guide for forming the self-assemblystructures 1802 that are used to define the second data pattern.

Step 1016 comprises removing protective layer 1502 on resist 1302 inservo regions 1104 (see FIG. 19). FIG. 19 is a cross-sectional view ofmaster template 1100 with protective layer 1502 removed according tostep 1016. Step 1018 comprises performing an etching process to etch theservo pattern in servo regions 1104 based on the servo pattern definedin resist 1302 (see FIG. 20). Step 1018 further comprises performing anetching process to etch the second data pattern in data regions 1106based on the self-assembly structures 1802 (see FIG. 20). FIG. 20 is across-sectional view of master template 1100 after the etching processaccording to step 1018. Any desired etching or removal process may beemployed in step 1018. Step 1020 comprises removing resist 1302 andself-assembly structures 1802 (see FIG. 21). FIG. 21 is across-sectional view of master template 1100 with resist 1302 andself-assembly structures 1802 removed according to step 1020. Mastertemplate 1100 may then be used to imprint magnetic disks with thedesired patterns.

Method 1000 may have multiple variations to achieve similar results.According to method 1000, servo regions 1104 are patterned with alithographically defined resist 1302. The lithographically-definedresist 1302 (see FIG. 14) allows fabricators to define the non-uniformisland sizes, shapes, and locations that are desired in servo regions1104. Data regions 1106 are patterned with self-assembly structures 1802as opposed to a lithographically-defined resist. The self-assemblymaterials allow fabricators to define uniform islands in data regions1106 that are tightly-packed. To form self-assembly structures 1802,servo regions 1104 are masked with protective layer 1502 so that theself-assembly structures 1802 are not built in servo regions 1104. Withservo regions 1104 protected, self-assembly structures 1802 may then bebuilt in data regions 1106. After self-assembly structures 1802 areformed in data regions 1106, protective layer 1502 may be removed, anddata regions 1106 are patterned based on self-assembly structures 1802and servo regions 1104 are patterned based on resist 1302.

In the above embodiment, servo regions 1104 and data regions 1106 areetched in the same processing step (step 1018). In other embodiments,servo regions 1104 and data regions 1106 may be etched in separateprocessing steps. FIG. 22 is a flow chart illustrating another method2200 of defining servo patterns and data patterns for a patternedmagnetic media in an exemplary embodiment of the invention. Method 2200has steps (1002-1014) that are similar to method 1000 (see FIG. 10),which have the same reference number. These steps will not be describedagain for the sake of brevity.

After the self-assembly structures 1802 (see FIG. 18) are formed in step1014, the protective layer 1502 on resist 1302 in servo regions 1104 isnot removed as in method 1000 (see FIG. 10) in this embodiment. Withprotective layer 1502 remaining on servo regions 1104, step 2202 ofmethod 2200 comprises performing an etching process to etch the seconddata pattern in data regions 1106 based on the self-assembly structures1802 (see FIG. 23). FIG. 23 is a cross-sectional view of master template1100 after the etching process according to step 2202. Step 2204comprises removing protective layer 1502 on resist 1302 in servo regions1104 (see FIG. 24). FIG. 24 is a cross-sectional view of master template1100 with protective layer 1502 removed according to step 2204.

Step 2206 comprises forming a protective layer 2502 in data regions 1106(see FIG. 25). FIG. 25 is a cross-sectional view of master template 1100with protective layer 2502 formed according to step 2206. Protectivelayer 2502 may again comprise any type of protective material thatcovers and protects data regions 1106, and can later be selectivelyremoved without removing or damaging the underlying servo patterns.Examples of materials that can be selectively removed would includemetals such as aluminum or chromium. With data regions 1106 protected,step 2208 comprises performing an etching process to etch the servopattern in servo regions 1104 based on the servo pattern defined inresist 1302 (see FIG. 26). FIG. 26 is a cross-sectional view of mastertemplate 1100 after the etching process according to step 2208. Step2210 comprises removing protective layer 2502 in data regions 1106 (seeFIG. 27). FIG. 27 is a cross-sectional view of master template 1100 withprotective layer 2502 removed according to step 2210.

Step 2212 comprises removing resist 1302 and self-assembly structures1802 (see FIG. 28). FIG. 28 is a cross-sectional view of master template1100 with resist 1302 and self-assembly structures 1802 removedaccording to step 2212. Master template 1100 may then be used to imprintmagnetic disks with the desired patterns.

The above embodiments illustrate methods of fabricating master templateswhich are used to fabricate patterned magnetic media. Those skilled inthe art will appreciate that similar methods may be used to pattern amagnetic media directly.

Although specific embodiments were described herein, the scope of theinvention is not limited to those specific embodiments. The scope of theinvention is defined by the following claims and any equivalentsthereof.

1. A method of fabricating a template for patterned magnetic mediahaving servo regions and data regions, the method comprising:transferring a guide pattern onto a substrate in the data regions;building self-assembly structures on the guide pattern to define aself-assembly pattern in the data regions; transferring theself-assembly pattern into the substrate in the data regions to define adata pattern in the data regions; and performing processes other thanwith self-assembly structures to define a servo pattern in the servoregions.
 2. The method of claim 1 wherein performing processes otherthan with self-assembly structures comprises: transferring alithographically-defined resist pattern into the substrate in the servoregions to define the servo pattern in the servo regions.
 3. The methodof claim 2 wherein the steps of transferring the self-assembly patterninto the substrate and transferring the lithographically-defined resistpattern into the substrate are performed in the same processing step. 4.The method of claim 1 wherein transferring the guide pattern onto thesubstrate in the data regions comprises: depositing a base layer on thesubstrate; depositing a resist on the base layer in the data regions;patterning the resist with a lithographic process to define the guidepattern; transferring the resist pattern into the base layer in the dataregions to define the guide pattern in the data regions; and removingthe resist.
 5. The method of claim 4 wherein transferring theself-assembly pattern into the substrate in the data regions to definethe data pattern in the data regions comprises: etching around theself-assembly structures to transfer the self-assembly pattern into thesubstrate in the data regions; and removing the self-assemblystructures.
 6. The method of claim 5 further comprising: forming aprotective layer on the servo regions before building the self-assemblypattern on the guide pattern.
 7. A method of defining servo regions anddata regions for a patterned magnetic media, the method comprising:patterning the servo regions using lithographic processes; andpatterning the data regions using a combination of lithographicprocesses and self-assembly processes.
 8. The method of claim 7 whereinpatterning the data regions comprises: depositing a base layer on asubstrate; depositing a resist on the base layer; performing a firstlithographic process to define a guide pattern in the resist within thedata regions; forming a protective layer on the servo regions;transferring the guide pattern from the resist onto the base layer inthe data regions; and removing the resist in the data regions.
 9. Themethod of claim 8 wherein patterning the data regions comprises furthercomprises: building self-assembly structures on the guide pattern in thedata regions to define a self-assembly pattern; and transferring theself-assembly pattern into the substrate in the data regions to define adata pattern in the data regions.
 10. The method of claim 9 whereinpatterning the servo regions further comprises: removing the protectivelayer from the servo regions; performing a second lithographic processto define a servo pattern in the resist within the servo regions;transferring the servo pattern from the resist into the substrate in theservo regions; and removing the resist in the servo regions and theself-assembly structures in the data regions.
 11. The method of claim 10wherein transferring the self-assembly pattern comprises: etching theself-assembly pattern into the substrate.
 12. The method of claim 10wherein transferring the servo pattern comprises: etching the servopattern into the substrate.
 13. The method of claim 8 wherein the baselayer comprises a self-assembly monomer.
 14. The method of claim 8wherein the protective layer comprises one of aluminum or chromium. 15.A method of fabricating a template for a patterned magnetic media, themethod comprising: performing a first lithographic process to define aservo pattern in servo regions that includes non-uniform portions;performing a second lithographic process to define a guide pattern in abase layer formed in data regions of a substrate; transferring the guidepattern into the base layer in the data regions; forming self-assemblystructures on the guide pattern to define a self-assembly pattern in thedata regions; transferring the self-assembly pattern into the substratein the data regions to define a data pattern in the data regions that isuniform; and transferring the servo pattern into the substrate in theservo regions.
 16. The method of claim 15 wherein performing the firstlithographic process to define the servo pattern in the servo regionscomprises: depositing a resist; patterning the resist with the firstlithographic process to define the servo pattern in the servo regions;and forming a protective layer on the servo regions.
 17. The method ofclaim 16 wherein performing the second lithographic process to definethe guide pattern in the data regions comprises: patterning the resistwith the second lithographic process to define the guide pattern in thedata regions.
 18. The method of claim 17 wherein transferring theself-assembly pattern into the substrate in the data regions comprises:etching around the self-assembly structures to transfer the guidepattern into the substrate; and removing the self-assembly structures.19. The method of claim 18 wherein transferring the servo pattern intothe substrate in the servo regions comprises: removing the protectivelayer on the servo regions; forming a protective layer on the dataregions; etching around the resist in the servo regions to transfer theservo pattern into the substrate; and removing the protective layer onthe data regions.
 20. The method of claim 19 wherein the protectivelayer comprises one of aluminum or chromium.